Add Cookstyle 6.1 release notes (#593)

* Add Cookstyle 6.1 release notes

Signed-off-by: Tim Smith <tsmith@chef.io>

* Update RELEASE_NOTES.md

Signed-off-by: Tim Smith <tsmith@chef.io>

Co-Authored-By: pete higgins <pete@peterhiggins.org>

* Update RELEASE_NOTES.md

Signed-off-by: Tim Smith <tsmith@chef.io>

Co-Authored-By: pete higgins <pete@peterhiggins.org>

* Update RELEASE_NOTES.md

Signed-off-by: Tim Smith <tsmith@chef.io>

Co-Authored-By: pete higgins <pete@peterhiggins.org>

* Update RELEASE_NOTES.md

Signed-off-by: Tim Smith <tsmith@chef.io>

Co-Authored-By: pete higgins <pete@peterhiggins.org>

* Update RELEASE_NOTES.md

Signed-off-by: Tim Smith <tsmith@chef.io>

Co-Authored-By: Ian Maddaus <IanMadd@users.noreply.github.com>

* Update RELEASE_NOTES.md

Signed-off-by: Tim Smith <tsmith@chef.io>

Co-Authored-By: Ian Maddaus <IanMadd@users.noreply.github.com>

* One last edit

Signed-off-by: Tim Smith <tsmith@chef.io>

Co-authored-by: pete higgins <pete@peterhiggins.org>
Co-authored-by: Ian Maddaus <IanMadd@users.noreply.github.com>

RELEASE_NOTES.md

@@ -1,3 +1,66 @@
+## Cookstyle 6.1
+
+### 5 New Cops
+
+#### ChefModernize/NodeRolesInclude
+
+The `ChefModernize/NodeRolesInclude` cop detects cookbooks that use `node['roles'].include?('foo')` to see if a particular role has been applied to a node. Use the simpler `node.role?('foo')` helper instead.
+
+`Enabled by default`: True
+
+`Autocorrects`: Yes
+
+#### ChefDeprecations/PowershellCookbookHelpers
+
+The `ChefDeprecations/PowershellCookbookHelpers` cop detects cookbooks that use the deprecated `Powershell::VersionHelper.powershell_version?` helper from the `powershell` cookbook. Chef Infra Client provides information on the installed PowerShell release at `node['powershell']['version']` and Chef Infra Client 15.8 and later includes a new `powershell_version` method which should be used when possible.
+
+`Enabled by default`: True
+
+`Autocorrects`: Yes
+
+#### ChefCorrectness/ConditionalRubyShellout
+
+The `ChefCorrectness/ConditionalRubyShellout` cop detects resources that use unnecessary Ruby code in `not_if` and `only_if` conditionals to shellout when a string can be used to avoid additional complexity.
+
+Shelling out with ruby:
+```ruby
+cookbook_file '/logs/foo/error.log' do
+  only_if { system('wget https://www.bar.com/foobar.txt -O /dev/null') }
+end
+```
+
+Shelling out without Ruby:
+```ruby
+cookbook_file '/logs/foo/error.log' do
+  only_if 'wget https://www.bar.com/foobar.txt -O /dev/null'
+end
+```
+
+`Enabled by default`: True
+
+`Autocorrects`: Yes
+
+#### ChefSharing/IncludePropertyDescriptions
+
+The `ChefSharing/IncludePropertyDescriptions` cop detects resource properties that don't include a description value. The `chef-resource-inspector` command displays the description value in resource properties and that description can be used to automatically generate documentation.
+
+`Enabled by default`: False
+
+`Autocorrects`: No
+
+#### ChefSharing/IncludeResourceDescriptions
+
+The `ChefSharing/IncludeResourceDescriptions` cop detects resources that don't include a description. The `chef-resource-inspector` command displays the description value in resources and that description can be used to automatically generate documentation.
+
+`Enabled by default`: False
+
+`Autocorrects`: No
+
+### Other Changes
+
+- `ChefModernize/PowershellInstallWindowsFeature` now correctly identifies the required Chef Infra Client release as 14.0 and later.
+- The `WindowsVersionHelper` cop has been moved to the `ChefDeprecations` department and now includes autocorrection for each of the helpers it identifies.
+
 ## Cookstyle 6.0
 
 ### RuboCop 0.80.1 Engine